Smart plant growth system

ABSTRACT

An aeroponic plant-growth system includes growth space and a control unit that may be assembled using factory made modules. The growth space includes layers at different heights, and each layer includes plant holders and misters positioned to apply a mist to roots of plants in the plant holders. The control unit employs a controller to execute a program that operates a liquid supply system to provide liquid flows to the misters in the layers. Each of the liquid flows may be regulated according to the height of the layers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent document claims benefit of the earlier filing date of U.S.provisional Pat. App. No. 62/631,041, filed Feb. 15, 2018, which ishereby incorporated by reference in its entirety.

BACKGROUND

Indoor systems have been developed for growing plants. For example,hydroponic systems can grow plants without soil, e.g., with rootssuspended in air, liquid or other media and plant nutrients provided inan aqueous solution that may be applied to the roots. A hydroponicsystem that employs aeroponic techniques, e.g., with plant rootspredominantly suspended in the air and nutrient solution delivered tothe roots in a mist, is described in U.S. Pat. App. Pub. No.2016/0021836, entitled “Aeroponic Growth System Wireless Control Systemand Methods of Using,” published Jan. 28, 2016, which is herebyincorporated by reference in its entirety. Such indoor plant growthsystems may be assembled using factory-made modules, with each modulebeing capable of growing a plant, a few plants, or a few dozen plants.

A commercial indoor plant growth facility would typically require manyplant growth modules arranged within the available space in a building.The modules need to be connected to infrastructure of the building suchas a water supply, drain pipes, and electrical power, and control and/ormonitoring systems may also need to be connected to the modules and tothe available infrastructure. Even with the currently available plantgrowth modules that may integrate many systems for satisfying plantgrowth needs, setting up and operating a large scale plant growthfacility that efficiently uses available indoor space and infrastructureand that promotes high crop production and plant growth can be a complextask.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram illustrating a side view of a plant growthsystem having a row that includes a control unit module and multi-layer,growth space modules.

FIGS. 1B and 1C are block diagrams illustrating top views of a plantgrowth system including multiple rows.

FIG. 2 is a block diagram illustrating fluid supply in a multi-layerplant growth system.

FIG. 3 shows an expanded perspective view of a tub/tray assembly used ina plant growth space.

FIG. 4 shows an expanded perspective view of a block of a plant growthspace including multiple tub/tray systems that form a drawer for growingplants.

The drawings illustrate examples for the purpose of explanation and arenot of the invention itself. Use of the same reference symbols indifferent figures indicates similar or identical items.

DETAILED DESCRIPTION

In accordance with one aspect disclosed herein, a plant growth systemmay includes modules that provide multiple stacked levels for growingplants. Each level may include one or more drawers that may be slid outfor horticultural operations such as planting, repotting, or harvestingof plants or maintenance operations such as cleaning, maintenance, orrepairs. The drawers may be vertically stacked to improve yield peravailable floor space at a plant growing facility. Growth space modulesincluding the stacks of drawers may further be organized into rows thatmay share resources such as a control module including a row controller,a dosing system, and a liquid supply system. Each row may be logicallysplit into layers, each layer corresponding to blocks of drawers atsubstantially the same height in different plant-growth modules.Operations such as supply of water or nutrient solution to plants may beperformed on individual levels. Further, a multi-row bank of modules mayinclude space for an aisle between two of the rows in the bank, and eachrow of modules may be mobile as a unit. The location of the aisle may bechanged by moving a row of modules next to the aisle into the spaceformerly used for the aisle, so that a new aisle opens up on an oppositeside of the moved row.

A plant growth system in accordance with one implementation of theinvention includes two main portions, a growth space (GS) and a controlunit (CU). The growth space includes structures for holding and growingplants and includes devices for providing for the needs of the plants,e.g., lights, ventilation systems, and nutrient applicators. The growthspace may also include sensors for monitoring the plants and/or theother devices in the growth space. The growth space may be provided,constructed, or assembled using one or more “growth space modules.” Thecontrol unit, which may be a distributed or centralized system, controlsand monitors all devices in the system and may be provided, constructed,or assembled using one or more “control unit modules.”

FIGS. 1A and 1B illustrate an implementation of a plant growth system100 using multiple section 110 to provide the growth space. Inillustrated configuration, each section 110 includes stacked blocks 112,and each block 112 contains one or more tubs 114. Tubs 114 are thesmallest module of the growth space in plant growth system 100. Ingeneral, one or more tubs 114, e.g., four tubs 114 in FIG. 1A, may beassembled horizontally into one block 112, and multiple blocks 112,e.g., Z blocks 112 in FIG. 1A, may be stacked vertically to form amulti-layer section 110. Sections 110 may, in turn, be arranged in oneor more rows. This modular hierarchy for the growth space may beconstructed from factory-made modules, and the factory-made modules mayreside at any of the different levels of the hierarchy. An entiresection 110 including multiple blocks 112, for example, may be assembledat a factory and then shipped to a plant-growth facility as anintegrated growth space module, and factory-made sections 110 may thenbe positioned and set up at the plant growth facility. Alternatively,each section 110 may be assembled at the plant-growth facility usingblocks 112 or tubs 114 that were delivered to the facility from amanufacturer. Accordingly, blocks 112 or tubs 114 may be consideredgrowth space modules that are building blocks of the growth space at aplant growth facility.

FIG. 1A shows a side view of a row including multiple sections 110 ofthe growth space of plant-growth system 100. FIG. 1A further illustratesan example implementation in which sections 110 in a row provide amultiple-layer space for growing plants. Each layer, as noted above, mayinclude a set of tubs 114 that are at the same level or height andprovide space for the roots of plants in tubs 114 with the foliage ofthe plants growing in open space above tubs 114. Each layer may furtherinclude plant-growth devices 116 such as lighting, ventilation fans, andplumbing that deliver light, air, and water or nutrient solution toplants in the layer. The height of each layer may vary for differentlayers. More particularly, each layer may employ blocks 112 havingdimensions chosen so that the vertical clearance between tubs 114 andoverlying plant growth devices 116 in the blocks 112 will be sufficientfor a type and growth stage of a plant to be grown in the layer.

FIG. 1B shows a top view of system 100 and illustrates how sections 110in a growth space may be grouped or organized in multiple rows on thefloor of a plant growth facility. For example, a specific section 110may have a footprint that occupies a set amount of floor space, e.g., 1m², and the number and arrangement of sections 110 at a facility maydepend on the floor plan of the facility. Each section 110 at thefacility may be assigned to a specific row number, e.g., 1 to X, and aspecific section index, e.g., 1 to Y, within the assigned row. Eachsection 110 may thus be uniquely identified by a pair of coordinatescorresponding to the row number and the section index of the section110. The number Y of sections 110 in a particular row and the number Xof rows in a plant-growth facility may be chosen according to theavailable floor space in the plant-growth facility. Although FIG. 1Billustrates a configuration in which rows 1 to X are straight, moregenerally, a row may be a curved, irregular, or any one-parameterarrangement or a sequence of sections 110.

Each section 110 in system 100 has a height, e.g., 2 m, and may includemultiple layers that are distinguished by a layer index, e.g., 1 to Z.Each block 112 specifically corresponds to the growth space within aspecific section 110 and a specific layer of the section 110, and eachblock 112 may thus be uniquely identified by a triplet of coordinates,e.g., (1,1,1) to (X,Y,Z), corresponding to row number, the sectionindex, and the layer index. System 100 is scalable and flexible in thatthe number X or rows, the maximum number Y of sections 110 in a row, andthe maximum number Z of layers in each section 110 may be selected ormay vary as needed to efficiently accommodate or fill almost anyavailable space in a facility. It may be noted that some rows may havefewer than the maximum number Y of sections per row and some sections110 may have fewer than the maximum number Z of layers per section.

Each section 110, block 112, or tub 114 may have its own local controlunit. For example, each section 110 may be formed (vertically) bystacking several blocks 112 together and connecting a Sectional ControlUnit (SCU) 118 on top of the section 110. Vertically, each sectioncontrol unit 118 may provide power to each block 112 in its section 110and may control/monitor all devices in the section 110. Horizontally,all section control units 118 in a row and a control unit module 120 forthe row may link together to form a network. Through this network, anSCU 118 may communicate with a host, e.g., a control unit 120 that runsthe row of sections 110 or a master controller (not shown) that controlsthe entire system 100 or the entire plant growth facility.

SCUs 118 being at the top of section 110 facilitates direct connectionof SCUs 118 to conventional facility infrastructure, e.g., to standardelectrical outlets, provided above sections 110. The overhead powerconnections may simplify electrical power distribution for a verticallystacked growth space. For example, the maximum number Z of layers at afacility may depend on the height of each layer and total ceiling heightof the facility. Each layer requires electrical power, and the maximumpower required for each section 110 can be calculated based on thenumber of layers and respective distances between SCU 118 and the layersof the associated section 110. This makes the length and required gaugeof all wire and cable within the same section 110 easy to calculatesince cables from each SCU 118 predominantly run in the verticaldirection, and an entire section 110 with layer heights specific to aplant growth facility can be built and tested during production of thesection 110 at a factory. SCU 118 thus facilitates or enablesfactory-built cabling as opposed to requiring custom wiring at the plantgrowth facility. In contrast, a system employing horizontal wiring andcabling may require that the number, size, or routing of wires or cablesextending through a section 110 depends on a number of sections 110 thatmay be strung connected together, which may be unknown when a section110 is being built at a factory. Use of SCU 118 in each growth-spacesection 110 may facilitate set up of a plant growth facility because theSCUs 118 may be directly connected to conventional facilityinfrastructure, e.g., to standard electrical outlets, provided above thesections 110.

SDU 118 can also play a critical communication/networking role in system100. To form a complete facility system, SCUs 118 in a row may beconnected with the control unit module 120 for the row using anaddressable communication link such as defined by the RS485communication standard. With the distance between and across twoadjacent SCUs 118 being known during module manufacture, a portion ofthe communication link may be installed in each section 110 at thefactory and daisy-chained together at the plant growth facility.Alternatively, wireless network communication could be employed in anetwork including SCUs 118 and control unit module 120 in a row.

In addition to communications and distributing power (e.g., for lights,fans, and sensors) to each layer or block 112 in a section 110, each SCU118 may also be the local host for its section 110 and may control andmonitor all growth related activities in its section 110. For example,each SCU 118 may: control power to lights, fans, sensors, and otherdevices in its section 110; monitor power usage in its section 110 andgenerate an error message if abnormal power usage occurred; collect datathrough wired or wireless connections to sensors in the section 110;send sensor data to software run by control unit 120 or a facilitycontroller (not shown); and provide location or ID information so thatsoftware can identify each block 112 at each location in the growthspace and track operation and performance of blocks 112.

The implementation of FIGS. 1A and 1B has one control unit module 120per row. Control unit module 120 may be a type of factory-made controlmodule that differs from the growth space modules, e.g., differs fromsections 110. In the implementation shown in FIG. 1A, control unitmodule 120 contains infrastructure 130 including a controller 122, adosing system 124, and a liquid supply system 126 that a row of sections110 share.

Controller 122 may include a network-linked computing system thatcollects and processes data from sections 110 and executes software orfirmware to control plant-growth devices as needed to implement plansfor growth of plants. More particularly, controller 122 may include amicrocontroller on a printed circuit board connected to sensors, controlrelays, solenoid valves, and other control devices, for example, devicesin dosing system 124 and supply system 126. Controller 122 may beprogrammed to handle all row-level activities such as delivering wateror nutrient solution to each tub 114 in the sections 110 in a row andmonitoring and controlling dosing system 124 during nutrient dosingprocesses. Controller 122 also communicates with all SCUs 118 connectedto control unit module 120 and may operate sections 110 to workaccording to a growth plan. For example, controller 122 may operatedosing system 124 to mix water and nutrients specified by a growth planand may operate liquid supply system 126 to provide, on a plan-specifiedschedule, the resulting nutrient solution to plants growing in the tubs114 in that row. In particular, the controller may execute a program tooperate the dosing system 124 and thereby alter the supply of thenutrients so that the nutrient solution has different ratios orconcentrations of the nutrients for different plants or different plantgrowth stages. In one specific configuration, a manufacturer mayconstruct individual sections 110 and control units 120 and ship thesections 110 and control units 120 to a plant growth facility, and atthe plant growth facilities, multiple sections 110 may be arranged in arow and connected together and to share a control module 120.

Supply system 126 may include one or more reservoirs, one or more pumps,filters, valves and liquid return systems. Dosing system 124 may includecanisters of nutrients, solenoid valves connected to controller 122 andoperable to release nutrients into a reservoir in supply system 126.Dosing system 124 may further include sensors to monitor the resultingnutrient solution in the reservoir of supply system 126. Dosing system124 may further include an antifungal or other agent such as hydrogenperoxide that control unit 120 can employ to keep water or nutrientsolution free of mildew.

Power for sections 110 providing growth space may come down from theceiling in a plant growth facility using power cords as described above.The power cords do not need to be particularly thick or heavy becauseeach power cord may provide only the power needed by one section 110.Other than the power cords, all necessary wire/cable may bepre-connected in sections 110 at the factory and fixed within sections110. Sections 110 otherwise use fluid connections to control unit module120, so that a row of growth space may be easy to move even when system100 is running. In particular, sections 110 and the shared control unit120 may be physically connected, e.g., bolted, together and may haverollers or slides that facilitate movement of the row. Further, flexiblepower cords to sections 110 and flexible facility plumbing linesconnected to control unit module 120 may provide slack so that some rowsin a plant-growth facility are movable relative to other rows. Thisenables a file-room style, also known as roller racks on tracks,movement of an access aisle 130. FIG. 1B, for example, shows that anumber X of rows of plant growth modules 110 may be arranged with spacefor one or more aisles 130 between adjacent rows. Each aisle 130 is anarea of floor space that allows personnel or machinery to access blocks114 of the growth space in one or both rows on either side of the aisle130. Some configurations may include rows that do not have any adjacentaisle that permits access to that row. For example, a set of four ormore rows may be arranged to provide only a single aisle 130 between twoof the rows. In that case, moving a row into an aisle can fill thataisle and create a new aisle located on the opposite side of the movedrow. FIG. 1B, for example, shows plant growth system 100 with aisle 130between rows corresponding to row numbers 1 and 2, providing access torows 1 and 2, but moving the row with row number 2 into aisle 130reconfigures plant-growth system 100 to have no aisle between rows withrow numbers 1 and 2. Instead, an aisle 130′ between rows with rownumbers 2 and 3 provides access to rows 2 and 3, as shown in FIG. 1C. Inthis way, one aisle may be sufficient for accessing any number of rowsin a growth space, and floor space used for sections 110 growing plantsmay be maximized.

FIG. 2 is a block diagram of a row of a multi-layer plant growth system200 and particularly illustrates details of liquid supply system 126 inan exemplary implementation of control unit module 120. In growth system200, control unit module 120 is associated with a growth space 210 thatmay include multiple sections 110 as shown in FIG. 1A. Growth space 210in the illustrated row is divided into a left growth space 212 and aright growth space 214 that may be located on opposite sides of controlunit 120. This arrangement of growth space 210 may allow growth system200 to employ smaller diameter plumbing since each plumbing line mayconnected to fewer, e.g., half, of the sections or other modules ofgrowth space 210.

Supply system 126 in FIG. 2 includes a reservoir 230 that receives waterthrough a solenoid valve 232 connected to a water supply 234 of theplant growing facility and receives plant nutrients from dosing system124. Controller 122 controls operation of valve 232 and dosing system124 to produce in reservoir 230 a nutrient solution having the desiredchemical composition, e.g., plan-specified concentrations of nutrientsin water, and a circulation pump 236 for reservoir 230 may serve to mixthe nutrients in the water and may employ a filter to keep the nutrientsolution clean. The minimum size of reservoir 230 generally depends onthe size of growth space 210 and how frequently plants need water ornutrients from reservoir. Reservoir 230 may further include sensors (notshown). For example, controller 122 may monitor a level sensor (notshown) to ensure an adequate level of liquid in reservoir 230. Atemperature sensor may be included in reservoir 230, and controller 122can keep water temperature in reservoir 122 in a desired range, forexample, by using a cooling coil (or other cooling system) 238 to cooldown water in reservoir 230.

A pump 240 connected through a one-way valve 242 and a filter 244supplies nutrient solution from reservoir 230 to a main irrigation line260, which is connected through respective solenoid valves 262 to branchirrigation lines that may be connected to respective layers in growthspace 210 or to individual blocks in the layers. To supply nutrientsolution to a specific layer or block of growth space 210, controller122 can activate pump 240 and turn on the valve 262 connected to thespecific layer or block of growth space 210 while valves 262 connectedto other layers or blocks are off. As a result, for the most part, onelayer or one block at a time receives nutrient solution. A pressuresensor 264 and a safety valve 266 may be connected, e.g., to mainirrigation line 260 or between main irrigation line 260 and reservoir230, and may be used to sense pressure in main irrigation line 260 or toremove pressure from main irrigation line 260 in the event that sensedpressure is too high, particularly if backpressure against pump 240 istoo high.

Irrigation pumps, such as pump 240, used in hydroponic or aeroponicsystems usually provide water or nutrient solution to roots only whenneeded. This means a pump for a block of growth space may be turned onand off frequently. Frequent on-off cycling uses energy inefficientlyand shortens pump life. Irrigation pump 240 may be shared by multiplelayers or blocks in growth space 210 to reduce the number of times pump240 needs to be turned on and off. Instead of shutting off pump 240 whenthe water needs of a block or layer are met, pump 240 may continue torun and solenoid valves 262 or similar devices may shift water flow fromone layer or block to another. Pump 240, which pumps water or nutrientsolution to the plants, may also be connected to drain water out fromreservoir 230 when needed. For example, pump 240 may be run continuouslyand switched from supplying nutrient solution to layers of growth space210 to draining liquid from reservoir 230.

In order to switch the flow from pump 240 among multiple tubs, blocks,or layers, the liquid pressure and flow of nutrient solution to thelayers of growth space 210 may need to be kept within an acceptablerange for supply to plants in the layers of growth space 210. One way tolimit pressure adds a manual safety, diverter, or pressure relief valve266 that diverts extra water out of main irrigation line 260, e.g., athigh pressure. Such a safety valve 266 may require manual adjustmentwhen irrigation piping condition changes. Also, a multiple-layer growthspace 210 may require one safety valve for each layer because each layerhas a different pressure under the same pump and needs a different setupfor its safety valve. In accordance with an aspect disclosed herein,each valve 262 may be a motorized ball valve, which has a controllableaperture for fluid flow, and controller 122 may use pressure sensor 264to measure liquid pressure and may adjust the size of the aperture ofthe valve 262 to maintain desired pressure or flow at the layerreceiving nutrient solution. More generally, valves may be anycontrollable variable aperture device. (As used herein, a controllablevariable aperture device is a device for controlling fluid flow that maybe set to fully open an aperture for fluid flow, to close the apertureto block fluid flow, or provide one or more aperture sizes that arebetween open and closed sizes.)

A second nutrient solution pump 250 with one-way valve 252 and filter254 is used in the illustrated implementation. Pump 250 connects to mainirrigation line 260 and may be a redundant backup of pump 240.Alternatively, reservoir 230 may be a dual reservoir including twoseparate compartment for mixing of nutrient solution. With or withoutdual dosing systems, dual reservoirs with a dual pump and filter systemscan provide continuous operation without interruption. In particular,nutrient solution may be dispensed from one compartment of reservoir 230while another batch of nutrient solution is being mixed in anothercompartment of reservoir 230. Dual reservoirs may make nutrient dosingeasier and more accurate.

Supply system 126 further includes a return pump 270 that may beconnected to remove excess nutrient solution that might otherwisecollect in the tubs in the layers of growth space 210. Return pump 270may return the nutrient solution from growth space 210 to reservoir 230for reuse. Alternatively, nutrient solution from reservoir 230 may bediscarded through a drain line 238 or 248 respectively from reservoir230 or pump 240 to a facility drain 280, e.g., to a sewer line or to acollection system for safe disposal of nutrient solution. The “smart”portion of control unit 120, e.g., controller 122 executing a program,may keep the liquid in reservoir 230 clean and containing the desiredconcentration of nutrients so that draining is minimized and the growthsystem may be more self-contained, only needing electricity and cleanwater, with efficient use and reuse of nutrients. Accordingly, liquidmay be drained rarely and only when strictly necessary.

A growth tub/tray assembly may be used in growth space 210 of FIG. 2 orin the growth space of system 100 of FIG. 1A to hold plants. Suchtub/tray assemblies provide operational flexibility that facilitateshorticultural operations (such as germinating seeds, transplantingseedlings, and growing and harvesting plants) and service operations(such as cleaning). For example, a tub/tray assembly (or at least a trayportion of the assembly) may be sized, e.g., have a total weight anddimensions suitable for one-person operations. The assembly or tray canthen be lifted, moved, and/or manipulated by a single person, which cansimplify horticultural tasks and improve employee efficiency in acommercial plant growth facility. In accordance with one aspectdisclosed herein, to further simplify horticultural tasks, a tub/trayassembly (or a small group of tub/tray assemblies) may be mounted asdrawers that are easily shifted in or removed from a plant growthsection that provides for the growth needs of one or more plants in thetub/tray assembly. In particular, a drawer may be slid so that a traycontaining plants may be removed from the growth space without damagingthe plants. Accordingly, some operations such as harvest and germinationthat do not require that much water, light, or nutrients can beperformed outside a plant growth space.

FIG. 3 shows an exploded view of an example of a tub/tray assembly 300that may be used in a growth space or a growth space module. Tub/trayassembly 300 includes an enclosure or tub 310 that provides space forplant roots and for containing water or a nutrient solution. Forexample, when tub/tray assembly 300 is in a growth space, water ornutrient solution in tub 310 may be drained out of tub 310 or otherwisekept below the level of plant roots for an aeroponic plant growthsystem, or water or nutrient solution in tub 310 may be kept at a levelhigh enough to submerge plant roots for a more conventional type ofhydroponic plant growth. Tub 310 may be an injection molded plastic tubhaving integrated inlets or outlets 312 for connection of plumbing fordraining or circulating liquid held in tub 310, and a root protector(not shown) may be provided in tub 310 to prevent roots from growinginto outlets 312. Each tub 310 may also include guide structures 314around and under a mounting area for a removable tray 320. Guidestructure 314 holds tray 320 and allows tray 320 to be slid forward andout of tub 310.

Tub/tray assembly 300 further includes removable plant tray 320 and atray holder 322 that may be mounted on top of tub 310, e.g., within amounting area defined by guide structures 314. Plant tray 320 includesan array of openings 324, which may be sized and spaced according to thedesired plant density in plant tub/tray assembly 300. Each opening 324in tray 320 may, for example, be sized to hold a small cup that holds aseed for germination, a larger cup that holds a seedling during earlygrowth stages, or an even larger net cup that holds a growing plantuntil harvest. Plant tray 320 is removable from tub/tray assembly 300and replaceable so that tub/tray assembly 300 can be fitted with a planttray 320 suited for the growth stage of the plants to be grown in planttub/tray assembly 300.

Tub/tray assembly 300 in the implementation of FIG. 3 further includesnutrient supply pipe or manifold 330 that supplies nutrient solution tomister nozzles 332 fitted on manifold 330. Manifold 330 with nozzles 332may be connected to an irrigation line that supplies water or nutrientsolution and may be mounted on tub 310 so that mister nozzles 332 arebelow tray 320 and positioned to spray nutrient solution onto the rootsof plants held in tray 320. Tub/tray assembly 300 may further include asupport for mounting of manifold 330 and to keep manifold 330 level.

Plant tub/tray assembly 300 may further include some electronics orother devices. For example, an image sensor, a weight sensor, or othersensors (not shown) in tub/tray assembly 300 may be used to measure ormonitor growing plants. Further, a tray ID such as an embedded RFID maybe integrated into plant tub/tray assembly 300, so that a tray 320 ortub 310 may be uniquely identified. Tray IDs help in tracking plantsbecause trays may be moved to different locations, e.g., differentblocks, within the growth space. In the implementation of FIG. 1A,section control unit 118 for the section 110 containing plant tub/trayassemblies 300 may collect IDs and sensor data from tub/tray assemblies300 in the section 110 and either processes the data locally ortransmits the data, e.g., to control unit 120 for further processing.

A block 112 as described with reference to FIG. 1A may contain one ormore plant tub/tray assemblies 300, and blocks 112 may be a basic unitor module built at a factory and provided to a plant growth facility. Insome implementations, each block 112 may include multiple tub/trayassemblies 300, a block or branch irrigation pipe, a block or branchdrainage pipe, lighting, an air movement device (e.g., fans or airducts), and other devices that assist plant growth, and such blocks 112may be vertically stacked as described above with reference to FIG. 1A.

Blocks 112 in a section 110 may employ a drawer system for tub/trayassemblies 300. FIG. 4, for example, illustrates a growth space block400 that may form a layer of a section 110. Growth space block 400includes one or more tub/tray assemblies 300 that may be connectedtogether as part of a unit 410 that fits in an enclosure 420. Unit 410may include multiple tub/tray assemblies 300, a drain pipe 412 connectedto outlets 312 on tubs 310, and a pressurized (input) pipe 414 for wateror nutrient solution that may be supplied to manifolds 330 within thetub/tray assemblies 300 forming unit 410. Rubber connectors or otherflexible or releasable plumbing or fittings (not shown) may connectdrain 412 to a row or the facility's plumbing and may connectpressurized pipe 414 to a source of water or nutrient solution, e.g., toliquid supply system 126 for the row. See FIG. 1A or 2.

Enclosure 420 includes a structure or frame that may be mounted on ormay form a part of the structure of a section, and enclosure 420 mayoccupy an area that is about the same as the floor space area of thesection. A height of enclosure 420 may be adjustable or selectedaccording to the desired height of the layer, e.g., according to theanticipated height of plants to be grown in block 400. Enclosure 420 mayfurther include mounting and height adjustment structures 424 forinstallation of over-plant devices 430. Over-plant devices 430 mayinclude, for example, lighting and ventilation devices, that provide theneeds of plants growing in block 400.

Enclosure 420 may further include guides 422 that are under or at thesides (not shown) of tub/tray assemblies 300 to facilitate sliding unit410 partly or fully out of enclosure 420, for example, for planting ofplants in unit 410, for rearranging plants to provide room for furthergrowth, or for harvest. In one implementation, unit 410 may be slid farenough that enclosure 420 does not interfere with removal of trays 320from tubs 310 while trays 320 contain plants. Alternatively, tub/trayassemblies 300 may be entirely removed from enclosure 420. Unit 410 maythus operate as a drawer mounted to slide relative to enclosure 420.Alternatively, unit 410 may be fixed in enclosure 420, and trays 320 mayoperate as drawers that slide relative to tubs 310.

Harvest often takes considerable time and labor at the site where plantsgrow. During harvest, growers often cannot plant or grow new plants in aportion of a growth space being harvested before all mature plants areharvested from that portion. After harvest, growers may need to taketime to plant seeds in place of the harvested plants. A drawer styletray such as described above with reference to FIGS. 3 and 4 with valves(manual or electronic valves) on pressurized pipe and drain pipe allowseach layer or unit 410 to be serviced individually while other layersare still operated normally. The drawer system also allows growers totake entire tray 320 of plants out of a growth space and immediatelyplace a new tray 320 of younger plants in that layer of growth space,while other layers still continue to operate normally. This may maximizethe utilization of plant growth systems that provide water, nutrientdosing, CO₂ enrichment, and lights needed for plant growth. Further,harvesting and packaging of plants in the removed tray may be completedat a different location from the plant growth facility, so thatharvesting may also be more efficient, for example, because a removeddrawer-style tray may be fed into an automatic harvest/cleaning/packingmachine for post growth processing.

Systems disclosed herein may support both submerged-root hydroponics andaeroponics and may switch from one to the other based on the situationsencountered during plant growth or based on the actual plants beinggrown. In particular, a valve that blocks (or permits) water in atub/tray from returning to a reservoir may close (or open) to switch ablock from aeroponic to submerged-root hydroponic operation (and viceversa). In one configuration, a system automatically may switch fromaeroponic operation to submerged-root hydroponic operation during apower outage (or to save power) while keeping plants alive.

Although particular implementations have been disclosed, theseimplementations are only examples and should not be taken aslimitations. Various adaptations and combinations of features of theimplementations disclosed are within the scope of the following claims.

What is claimed is:
 1. An aeroponic plant-growth system comprising: agrowth space including a plurality of layers respectively at a pluralityof heights, each layer comprising one or more plant holders and one ormore misters, each of the misters being positioned to apply mist toroots of a plant in at least one of the plant holders; and a controlunit comprising: a liquid supply system coupled to the misters in thelayers, the liquid supply system comprising: a pump; and a plurality ofvalves coupled to the pump and respectively to the layers; and acontroller configured to execute a program that continuously operatesthe pump while operating the valves to control a plurality of liquidflows to the misters in the respective layers, the operation of thevalves regulating the liquid flows according to the heights of therespective layers.
 2. The system of claim 1, wherein the growth spacefurther comprises: an enclosure; and the plant holders comprise aplurality of tub/tray assemblies stacked vertically in the enclosure,each of the tub/tray being in a different one of the layers of thegrowth space.
 3. The system of claim 2, wherein each of the tub/trayassemblies includes a tub and a tray mounted in the tub.
 4. The systemof claim 3, wherein the trays are mounted to slide out of the respectivetubs for removal while the trays hold plants.
 5. The system of claim 1,further comprising irrigation plumbing extending from the liquid supplysystem to the misters, the irrigation plumbing permitting removal of anyof the drawers while the irrigation plumbing continues service to othersof the drawers.
 6. The system of claim 1, wherein the controlleroperates the pump to keep the pump continuously on while the controllerturns on the liquid flow to one of the layers and turns off the liquidflow to another of the layers.
 7. The system of claim 1, wherein thevalves have adjustable aperture sizes.
 8. The system of claim 7, whereinthe controller operates a selected one of the valves to provide theliquid flow to the layer coupled to the selected valve and shut off theliquid flows through others of the valves, the controller selecting theadjustable aperture size of the selected valve based on the height ofthe layer connected to the selected valve to provide the liquid flowfrom the selected valve with a pressure acceptable for the misters tosupply mist to plants.
 9. The system of claim 8, further comprising apressure sensor coupled to sense liquid pressure in the liquid supplysystem, wherein the controller operates the selected one of the valvesto have the adjustable aperture size be selected additionally based on apressure sensed by the pressure sensor.
 10. The system of claim 7,wherein each of the valves comprises a motorized ball valve.
 11. Thesystem of claim 1, wherein: the control unit comprises a factory-madecontrol module; and the growth space comprises a plurality offactory-made sections that are connected together and connected to thefactory-made control unit at a plant growth facility.
 12. The system ofclaim 1, wherein the control unit further comprises: a reservoir; and adosing system coupled to supply water and nutrients to the reservoir,the controller controlling operation of the dosing system to create anutrient solution in the reservoir, wherein: the liquid supply systemsupplies the nutrient solution from the reservoir in the liquid flows tothe misters in the plurality of layers.
 13. The system of claim 12,wherein the controller executes the program to operate the dosing systemand thereby alter the supply of the nutrients so that the nutrientsolution has different ratios of the nutrients for different plants ordifferent plant growth stages.
 14. The system of claim 12, wherein thecontroller executes the program to operate the dosing system to dispensean agent that keeps the nutrient solution clean.
 15. The system of claim1, wherein the controller operates the valves to turn the liquid flowson and off and when any of the valves provides liquid flow to themisters, the controller operates the valve to maintain a desiredpressure of the liquid flow at the misters regardless of the height ofthe layer containing the misters.
 16. The system of claim 1, wherein thecontroller further operates the valves to maintain a desired pressure ofthe liquid flow at the misters regardless of the height of the layercontaining the misters.
 17. An aeroponic plant-growth system comprising:a growth space including a plurality of layers respectively at aplurality of heights, each layer comprising one or more plant holdersand one or more misters, each of the misters being positioned to applymist to roots of a plant in at least one of the plant holders; and acontrol unit including a liquid supply system coupled to the misters inthe layers, the liquid supply system comprising: a pump providing aliquid flow; a plurality of valves coupled to the pump and respectivelyto the layers; and a controller configured to execute a program thatcontinuously operates the pump while operating the valves to turn on oneor more of the valves and thereby start the liquid flow to one of thelayers when turning off one or more of the valves and thereby stop theliquid flow to another of the layers.